Times and technologies are changing daily. Relative electronic techniques are also progressing day by day. The functions of electronic product are enhanced abruptly. Relatively, the peripheries of computer are expanded more and more for providing required necessities in daily lives. The scanner is then a common periphery for a computer. The main function of a scanner is to retrieve an image of scanned document and convert the retrieved image into electronic signals. The electronic signals are again input into a computer to proceed image treatment.
Please refer to FIG. 1A, which shows an example of flatbed scanner of typical type commonly seen in current market. Mainly, a document window glass 15 is provided on the upper surface of the shell 11 of a scanner 1. An optical chassis 14 is driven by a driving apparatus 12 to proceed linear motion along the direction of a guiding rod 13 inside the hollow shell 11 and proceeds image scanning job on a reflection document 2 placed on the document window glass 15.
The above-described flatbed scanner 1 is used to proceed scanning motion of a reflection document 2 (such as photograph or paper). While certain scanning job is proceeded on a transmission document 3 (e.g. transparency) in current market, please refer to FIG. 1B, of which the transmission document 3 is placed behind a transmission document carrier 16. The transmission document carrier 16 fixes the transmission document 3 with a manner of clamping. A second light source 142 again provides “light” incident upon the transmission document 3. An optical chassis 14 is driven by a driving apparatus 12 to proceed linear motion along the direction of a guiding rod 13 inside the hollow shell 11 and proceeds image scanning job on a transmission document 2 placed on the document window glass 15.
Since, when “light” is incident upon the transmission document 3 and an image scanning job is proceeded by the optical chassis 14, a phenomenon of Newton Ring will be occurred because of “light” passing through the document window glass 15, so the scanned out quality is inferior. Therefore, there is an improved scanner of flatbed type to execute image-scanning job of the transmission document 3 in current market. Please refer to FIG. 2, wherein an open groove 111 is arranged at one side surface with transmission document carrier 16. By the application of the transmission document carrier 16 capable of being taken out, it can achieve the function of dual scanning for both the reflection document 2 and the transmission document 3. Namely, when applying reflection typed scanning mode, the reflection document 2 is placed on the document window glass 15 for proceeding scanning job on reflection document 2. While applying transmission typed scanning mode, the transmission document is clamped and fixed by the transmission document carrier 16, and then the transmission document carrier 16 is placed into the open groove 111 for proceeding scanning job on transmission document 3.
In summarizing above description, in order to apply dual scanning modes for both the reflection document 2 and the transmission document 3 for prior flatbed scanner 1, the open groove 111 must be arranged at the shell 11. This will cause complicated structure design and drawback of higher cost. Therefore, in order to reduce cost and promote competition ability for industry, the problem of flatbed scanner 1 is really required urgent solution and breakthrough.